LARGE1 and proximal spinal muscular atrophy: We next addressed the potential of LARGE1 to serve as a minimal invasive biomarker by investigating the level in serum samples derived from adult and pediatric SMA patients at baseline visit: the investigation of 8 adult patients (4 responder and 4 non-responder) revealed a significant increase of LARGE1 level in serum samples derived from the patient cohort compared to controls (n = 5).